Two-stage attachment for cutting, crimping etc, and mechanical method thereof

ABSTRACT

A multifunctional tool for cutting (crushing or shearing), crimping, perforating and other operations that require high force to be applied to a small area, plus a method of designing such tools for a variety of applications. A sectorial eccentrically pivoted cam is implemented as a part of a lever of first stage. A working surface of this cam fits precisely onto a corresponding surface of a lever of a second stage so that when the cam is partially rotated about its pivot, the lever of second stage receives impetus to move about its own pivot at hyperbolic trajectory and a distance lesser than that of the lever of first stage.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority to U.S. Provisional Patent Application No. 60/510,166 filed on Oct. 8, 2003

FEDERALLY SPONSORED RESEARCH

None.

SEQUENCE LISTING

None.

BACKGROUND OF THE INVENTION

This invention is related to a field of tools used by various industries, more particularly of those for cutting metal rods, bolts, cables and like, crimping and other operations for which severing or squeezing force is essential.

The art currently existing in this field is very prolific and ingenious. It is, however, rather function specific, hence being unable to help minimizing the amount of hardware that one must acquire and maintain in a course of doing business. Moreover, most of tools that are designed for performing a certain duty do not provide for any versatility even within a definition of such duty.

Versatility never comes without a sacrifice of some of the merits immanent to single-purpose implements. For instance, two separate tools usually had to be purchased in the past, one for cutting metal rods or bolts and another for cutting cables, since well known bolt cutters with straight edge jaws perform on cables very poorly. This problem, as well as bringing the cutting action very close to a common pivot point of cutting blades while substantially reducing the size of those blades, was effectively solved by the invention of U.S. Pat. No. 6,185,825 to Olson, Feb. 13, 2001 (FIGS. 1A-B).

However, a cutter of that invention commands a use of highly specialized hardware for sharpening of the former, as needed for cable cutting (when cutting edges wear out and dull even slightly, they shear throughout most of the cable's thickness and then “chew in” some wires between blades), and after only few sharpening cycles the entire tool must be discarded because there is no provision for replaceable blades. Further, shearing blades enclosed inside one another generate width exceeding that of “squeezing/crushing” cutters, adding limitation to the tool's usefulness.

The invention of U.S. Pat. No. 5,862,597 to Juros, Jan. 26, 1999 (FIGS. 2A-C), makes it possible to bring the cutting action as close to a point of applied force as physically allowable, but doing so comes at a cost. Considering structural properties of materials involved, a tool's width herein must somewhat exceed that of most prior and current art, thus restricting it's use in narrow openings (such as between pipe flange faces). Also, as a “penalty”for use of fully circular eccentrically pivoted boss (to multiply the force), this tool's handles must be opened to a notably greater angle, thus practically nullifying a benefit of their being shorter, but making them unsafe and uncomfortable instead. A lack of inexpensive and easily replaceable blades also remains as in most existing tools. Further shortcomings will be outlined below.

Inventions of WO Pat. #9505271 to Cooper IND INC, Feb. 23, 1995 (FIG. 3A), U.S. Pat. No. 6,226,874 to Jansson, May 8, 2001 (FIG. 3B) and conventional, widely sold bolt cutter (FIG. 3C) along with many others featuring a similar configuration, present another well known approach to a subject of the cutter's longevity, expressed in a provision of various means for adjusting the blades after sharpening of the same. Nevertheless, eventually one still has to replace blades that do cost nearly as much as a whole new tool.

The issue of replaceable blades was specifically addressed by inventions of EP0011545 to Muller, May 28, 1980 (FIG. 4A) and U.S. Pat. No. 5,898,998 to Deville, May 4, 1999 (FIG. 4B), but the solution suggested therein, while being suitable for usage in many of tool designs, is not entirely satisfactory. It weakens a blade support and does not facilitate a uniform transfer and distribution of tensions within a metal structure of the blade and the blade support, thus speeding up an accumulation of a fatigue in the structure.

All four of latter inventions suffer from an obvious departure from keeping the cutting action near the point of applied force, so these tools, once again, demand an application of greater force to handles.

An illustrative example of loss of versatility in favor of improving a narrow aspect can be seen in the invention of DE Pat. No. 3,402,544 to Hoffmann, Aug. 8, 1985 (FIG. 4C). It completely eliminates such well-known nuisance as when a material that is being cut slips farther away from the point of applied force. In exchange, this improvement renders such cutter practically incapable of cutting anything thinner then, roughly, a width of a gap between jaws opened to about two-thirds of their capacity.

A field of tools featuring power sources is, for the purpose of this discussion, represented by inventions of U.S. Pat. No. 4,587,732 to Lind, et all, May 13, 1986 (FIG. 5A), U.S. Pat. No. 4,760,644 to Yirmiyahu, et all, Aug. 2, 1988 (FIG. 5B) and JP02002078988 to Oide, Mar. 19, 2002 (FIG. 5C). These tools can readily utilize quite a variety of attachments for different operations. But such attachments shall come at relatively high cost and, except JP02002078988, would very doubtfully be easily demountable. Beside that, these inventions solve practically non of the other shortcomings of above cited prior art.

Mostly the operations falling into a category of “cutting” had herein been looked upon so far. This was done in an attempt to make it evident that a challenge of finding an optimal combination of most efficient means for accomplishing even slightly varying tasks does stand unanswered by the existing art.

The present invention introduces not only such combination, but also far greater degree of versatility while sacrificing very little of some and nothing at all of the other benefits that elements of the combination do provide individually.

With the exception of U.S. Pat. No. 6,185,825 to Olson (FIGS.1A-B) whose tool utilizes one stage lever action, other previously discussed manual cutters comprise handles as levers of first stage and blades as levers of second stage. During a thorough search of prior art no attempts to arrange two-stage lever action within blades (as per the present invention) were discovered.

OBJECTS AND ADVANTAGES

A primary object of the present invention is to introduce an attachment that is readily adaptable to existing and available force multiplying devices as well as to those yet to come, regardless of their being either manual or with power source.

Two-stage attachment must utilize an approach not found in it's full scope in the prior art of the related field. It shall combine, to a maximal extend, beneficial qualities of prior art and those newly suggested hereby, while keeping sacrifices to a minimum.

List of objects of the present invention includes:

-   -   1) Making the attachment multifunctional and long lasting by         creating of several sets of blades, detachable and exchangeable,         whereby each set is being designed for it's own specific         function, namely         -   a) cutting bolts, rods and like in squeezing/crushing             manner,         -   b) cutting bolts, rods and like in shearing manner,         -   c) cutting cables and steel wire ropes,         -   d) crimping hose end fittings and cable end connectors,         -   e) perforating, i.e., punching holes through an edge of a             sheet metal so that fastening of two or more sheet metal             work pieces can occur,         -   f) concentric perforating for making small washers, gaskets             and o-rings,         -   g) grommet installation onto edges of various stiff             materials,         -   h) permanent labeling, i.e., imprinting characters onto             metal for marking and/or sealing commenced by authorized             persons.     -   2) Making an overall size of the attachment in all three of it's         above listed cutting modes (a, b and c) plus crimping mode d),         perforating mode e) and labeling/sealing mode h) the same as or         lesser than that of most prior art cutters, so that it does         -   a) fit just as well or better into various restricted             openings and gaps without changing of it's width (meaning             “open” position versus “closed”),         -   b) avoid necessitating longer handles and greater opening             angles of same while operating as part of manual tools.     -   3) Achieving a substantial reduction, in comparison with most of         the prior art tools, of a force needed to perform the cut or the         squeeze by making the cutting action to occur as close to the         point of applied force as it is possible without losing the         essence of the object 2).     -   4) Doing away with the slipping of the work piece in the         beginning of the cut by optimizing the angle between the jaws in         “open” position without any functional or dimensional sacrifice         whatsoever.     -   5) Optimizing the distribution of the structural tensions that         occur in an area of conjunction of the exchangeable blade and         the blade support, thus preventing an uneven buildup of metal         fatigue and an unsafe condition arising thereby.     -   6) Accomplishing higher degree of adaptability than that         available from the prior art tools, i.e., making the attachment         suitable for use with a plurality of the force multiplying         devices, both manual and with power source, even those made by         competing manufacturers, so that one can purchase the attachment         and readily use it with, for example, his/her old bolt cutter         handles.

The objects and advantages of the present invention are not limited to above listed. Other benefits will become evident in a course of acquainting oneself with following summary, drawings and descriptions.

SUMMARY OF THE INVENTION

The present invention, in a broad sense, is a two-stage lever arrangement designed to facilitate an improved input/output ratio within, at the same time lessening minimally necessary dimensions of, a hardware for an application of cutting and/or shearing, squeezing and piercing force. Such force can be applied by both manual devices and those featuring power sources.

A sectorial (as opposed to fully circular or elliptical) eccentrically pivoted cam is implemented as a part of a lever of a first stage. Consecutively, the cam imparts an impetus to another pivoted member, or a blade support, which is thus effectively becoming a lever of a second stage. An essential element of the present invention is the fact that it arranges for two-stage lever action to occur within the same spatial dimensions as those allowing for merely one-stage lever action in cases of known relevant prior art.

Means of linkage may, but do not necessarily have to, be provided between the cam lever and the blade support of each couple in a manner that such connection does not obstruct a functional movement of cam lever and blade support one relative to another. In a case when these means of connection are not provided, the contact between working surfaces is maintained by springs that may be of a plurality of shapes and located in various suitable places.

The blade support is made capable of accommodating a variety of interchangeable blades, which are, in turn, carrying out a useful work. The present invention thereby provides a good possibility of incorporation of several remotely related functions into one multifunctional implement.

Combination of following concepts, since the former has not previously been used in the related field and to that extend, is believed to constitute the Mechanical Method of the present invention:

-   -   a concept of sectorial eccentrically pivoted cam, combined as         one piece with lever of a first stage, imparting the impetus to         separately pivoted second-stage blade support, which allows to         arrange the two-stage lever action within spatial dimensions         same as, or lesser than, those accommodating merely one-stage         lever action of prior art,     -   a concept of adding presently uncharacteristic functions by an         introduction of exchangeable blades mounted in such manner that         bending, twisting, stretching and other tensions resulting from         a course of deforming a work piece are transmitted uniformly and         distributed evenly between the blade and the blade support.

To illustrate the Mechanical method of the present invention more comprehensively, two primary aspects are offered for consideration. Both prior art and the present invention make use of eccentrically pivoted force multiplying elements of sectorial rotation. However, such elements of prior art are fully circumferential, thus being excessively space- and material-consuming, and in most cases capable of serving only a very narrow purpose. Unlike so, the force multiplying element of the present invention is being partially circumferential, or segmental. As it shall become evident upon further studying of a Detailed description and Drawings, it affords one skilled in the art a great deal of flexibility in designing tools and machinery.

Another aspect heretofore is with regard to exchangeable blades, meaning both the way they are mounted and the resulting ability to vary their shapes and functions. Such mounting method puts a theoretical axis of connection of the blade to the blade support at certain angle to a theoretical axis of the attachment. Merely single small retaining screw per blade does suffice to keep it at place.

BRIEF DESCRIPTION OF DRAWINGS

1. FIGS. 1A and 1B are showing functional isometric view and exploded isometric view of prior art of U.S. Pat. No. 6,185,825.

2. FIGS. 2A, 2B and 2C are showing, respectively, exploded isometric view, general isometric view and plane view of prior art of U.S. Pat. No. 5,862,597.

3. FIGS. 3A, 3B and 3C are showing, respectively, plane view of prior art of WO9505271, plane view of prior art of U.S. Pat. No. 6,226,874 and plane view of widely available and well known bolt cutter of prior art.

4. FIGS. 4A, 4B and 4C are showing, respectively, views of exchangeable blade of prior art of EP0011545, plane view of prior art of U.S. Pat. No. 5,898,998 and plane view of prior art of DE Pat. No. 3,402,544.

5. FIGS. 5A, 5B and 5C are showing, respectively, general isometric view of prior art of U.S. Pat. No. 4,587,732, general isometric view of prior art of U.S. Pat. No. 4,760,644 and plane views of prior art of JP02002078988.

6. FIG. 6 is showing functional isometric view of the preferred embodiment of Two-stage attachment of the present invention.

7. FIG. 7 is showing exploded isometric views of movable members of the preferred embodiment of Two-stage attachment, from top to bottom: upper cam lever, upper blade support, upper exchangeable blade, lower exchangeable blade (crushing blades shown), lower blade support and lower cam lever.

8. FIG. 8 is showing partially exploded isometric view of the preferred embodiment of Two-stage attachment, movable members are shown as if were actually assembled, in “closed” position.

9. FIGS. 9A and 9B are showing plane schematic views of Two-stage attachment of the present invention in “open” and “closed” positions.

10. FIGS. 10A and 10B are showing isometric views of “open” and “closed” positions (one fulcrum plate is removed for viewing) of the preferred embodiment being attached to hydraulic power source such as that of U.S. Pat. No. 4,760,644.

11. FIGS. 11 a and 11 b are showing functional view of a manually operated version of Two-stage attachment of the present invention and plane view of the same being attached to handles of widely used store-purchased bolt cutter, in “partially open” position.

12. FIG. 12 is showing exploded isometric views of movable members of a manually operated version of Two-stage attachment, from top to bottom: upper manual cam lever, upper pared blade support, upper exchangeable blade, common slave pivot, lower exchangeable blade (shearing blades shown), lower pared blade support and lower manual cam lever.

13. FIG. 13 is showing partially exploded isometric view of the manually operated version of Two-stage attachment, movable members are shown in the same fashion as that of FIG. 8.

14. FIGS. 14A to 14F are showing, in the following order, pair of blade supports (14A) and sets of exchangeable blades for crushing (14B), shearing (14C), crimping (14D), perforating (14E) and labeling, or imprinting of characters (14F).

15. FIGS. 14G to 14K are showing, in the same order as above, sets of blades where each is made as one piece with blade support for possible use in small sizes of Two-stage attachment.

DRAWINGS—LIST OF REFERENCE NUMERALS

-   15(a, b)—cams, -   15(aX, bX)—pushing surfaces, -   16(a, b)—levers, -   16(Ra, La etc)—pad eyes, -   16H—spring holders, -   17(a, b)—master pivots, -   17(Ra, La etc.)—master pivot shafts, -   18(a, b)—rollers, -   19(a, b)—roller's axis, -   20—retaining screws, -   21(a, b)—cam levers, -   22(a, b)—blade supports, -   22(aX, bX)—yielding surfaces, -   22(aY, bY)—blade beds, -   23(a, b)—slave pivots, -   24(a, b)—apertures, -   25(a, b)—master pin orifices, -   26(a, b)—slave pin orifices, -   27(a, b)—cam slots, -   28(a, b)—blade support slots, -   29(a, b)—master pins, -   29(aa, bb)—slave pins, -   30(a, b)—linking springs, -   31(a, b)—keyed retaining ledges, -   32(a, b)—threaded holes, -   33(a, b)—grooved retaining shelves, -   34(a, b)—crushing blades, -   34(aY to 38 bY)—mounting surfaces, -   35(a, b)—shearing blades, -   36(a, b)—crimping blades, -   37(a, b)—perforating blades, -   38(a, b)—labeling blades, -   39(a, b)—mounting screws, -   40(R, L)—fulcrum plates, -   41(Ra, Rb etc.)—master pivot holes, -   42(Ra, Rb etc.)—slave pivot wells, -   43(Ra, Rb etc.)—mounting shaft wells, -   44(a, b)—mounting shafts, -   45—fasteners, -   46—retaining rings, -   47—actuating cam -   CTA—cam theoretical area -   PATA—prior art theoretical area -   S(R, L)—positioning springs, -   FH—fastening holes, -   FF—face flange, -   MP—mounting pad eyes -   48(a, b)—jointly pivoted blade supports, -   49(a, b)—horizontally offset pad eyes, -   50—common slave pivot, -   51(a, b)—manually actuated cam levers, -   52(a, b)—single pad eyes, -   53(R, L)—lesser fulcrum plates, -   54(R, L)—pivot grooves, -   55(R, L)—fastener holes, -   56—threaded spacer, -   57—short fasteners.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT—FIGS. 6 TO 14K.

A preferred embodiment of Two-stage attachment comprises two sectorial, as opposed to fully circular or elliptical, eccentrically pivoted cams, or cams 15 a and 15 b. Each of these cams is made as one piece with it's respective lever, namely levers 16 a and 16 b so that each cam and it's lever have one common pivot, or master pivot. Each of two master pivots 17 a and 17 b, in it's turn, consists of right and left master pivot shafts, accordingly, 17Ra, 17La, 17Rb and 17Lb.

Rear end of each of levers 16 a and 16 b forks into two coaxial vertically oriented pad eyes, shown as 16Ra, 16La, 16Rb and 16Lb, and rollers 18 a and 18 b are accommodated between these pad eyes. Outer rim surface of each of rollers 18 a and 18 b has shallow groove of triangular profile. Roller's axis 19 a and 19 b respectively are inserted through pad eyes 16 Ra, 16La, 16Rb and 16Lb and being kept at place by retaining screws 20 (same numeral for all four).

On both sides of levers 16 a and 16 b, in an area neighboring master pivot shafts, spring holders 16H (same numeral for all four) are arranged in order to retain ends of positioning springs SR and SL.

Two cam levers 21 a and 21 b are thereby being formed (shown on FIG. 7) Master pivot shafts 17Ra, 17La, 17Rb and 17Lb are, for the purpose of providing a necessary tensile strength of cam levers 21 a and 21 b, also made as one piece with the latter. Each of cam levers 21 a and 21 b is able to commence a predetermined sectorial, or partially rotary, motion around it's respective master pivot axis.

Rollers 18 a and 18 b serve, and more generally, cam levers 21 a and 21 b are designed for receiving a force that strives to rotate them about their master pivots, 17 a and 17 b (pivots herein are mentioned as such without reference to their right and left shafts), whereas such force can be applied by different means including, but not limited to, variously shaped actuating cams (like that, but not limited to, shown on FIGS. 10A-B, actuating cam 47) vectored by hydraulic, electric or combined power actuators, ratchet-type devices (not shown), etc.

Cams 15 a and 15 b feature working surfaces of convex arc-like shape, or pushing surfaces 15 aX and 15 bX. These surfaces are located, with relation to master pivots 17 a and 17 b (once again, mentioned as a whole) as being centers, at lower (cam 15 a) and upper (cam 15 b) outer edges of cams, in a plane view. In the preferred embodiment cam levers 21 a and 21 b are located in a symmetrical opposition to one another and at predetermined distance, with pushing surfaces 15 aX and 15 bX facing each other.

Two cam levers 21 a and 21 b, spatially organized in the above described way, are deemed herein as being a first of Two stages of the Attachment and the Mechanical method of the present invention. This statement shall be additionally supported upon further studying of present detailed description.

A second of Two stages of the Attachment and Mechanical method of the present invention is formed by two individually pivoted blade supports 22 a and 22 b, also symmetrically facing one another and located between cams 15 a and 15 b of cam levers 21 a and 21 b (as shown on FIG. 7).

Blade supports 22 a and 22 b feature concave working surfaces of arc-like shape, or yielding surfaces 22 aX and 22 bX, precisely adjacent to, accordingly, pushing surfaces 15 aX and 15 bX of cams 15 a and 15 b. Pushing and yielding surfaces of each cam-blade support couple (15 aX-22 aX and 15 bX-22 bX) are thereupon becoming arcs of imaginary concentric circumferences, of which centers lie on sides of cams 15 a and 15 b at precalculated distance from axis of master pivots 17 a and 17 b (mentioned the same way as twice above) respectively, thus creating a rotationally slidable contact between pushing and yielding surfaces of each cam lever-blade support couple (15 aX-22 aX and 15 bX-22 bX, shown on FIGS. 9A-B).

Blade supports 22 a and 22 b are pivoted by blade support pivot shafts, or slave pivots 23 a and 23 b. Rear ends of blade supports 22 a and 22 b have oval-shaped slave pivot apertures, or apertures 24 a and 24 b (shown in greater detail on FIG. 14A). Slave pivots 23 a and 23 b protrude through their corresponding apertures 24 a and 24 b so that blade supports 22 a and 22 b are able to commence predetermined sectorial, as well as linear (restricted by a length of apertures 24 a and 24 b) motion about their slave pivots 23 a and 23 b. Slave pivots 23 a and 23 b are hollow, and their length exceeds the thickness of blade supports 22 a and 22 b by approximately ½ of the latter. Slave pivots 23 a and 23 b may also be made of lesser outside diameter and supplemented by roller rings, or bearings (not shown), for the purpose of wear reduction.

Precisely through centers of above mentioned imaginary concentric circumferences master pin orifices 25 a and 25 b are drilled. Slave pin orifices 26 a and 26 b are drilled through sides of blade supports 22 a and 22 b at their upper front part. Cam slots 27 a and 27 b and blade support slots 28 a and 28 b are machined thereafter and master pins 29 a and 29 b and slave pins 29 aa and 29 bb are then being gently hammered into corresponding orifices heretofore in order to accommodate linking springs 30 a and 30 b. These springs are clipped onto pins 29 a, 29 aa, 29 b and 29 bb. Movable linkages between cam 15 a and blade support 22 a and between cam 15 b and blade support 22 b are thereby being established (shown on FIG. 7 and FIGS. 9A-B).

Further, blade supports 22 a and 22 b comprise exchangeable blade supporting surfaces, or blade beds 22 aY and 22 bY respectively. These are machined in such manner that when the Two-stage attachment of the present invention is in “open” position, their straight flat portions are parallel to each other (shown, for the purpose of this illustration, on FIG. 9A). An importance of this factor is explained in a chapter that describes operation of the preferred embodiment. Blade beds 22 aY and 22 bY also have keyed retaining ledges 31 a and 31 b, and threaded holes 32 a and 32 b in the same logical order, “a” to “a”, “b” to “b”.

All exchangeable blades, namely crushing blades 34 a and 34 b, shearing blades 35 a and 35 b, crimping blades 36 a and 36 b, perforating blades 37 a and 37 b and labeling blades 38 a and 38 b (shown on FIGS. 14B-F) are machined so that their mounting surfaces (from 34 aY to 38 bY) fit precisely onto blade beds 22 aY and 22 bY, while grooved retaining shelves 33 a and 33 b (these numerals are used for grooved retaining shelves on all sets of blades throughout) fit snugly over and behind keyed retaining ledges 31 a and 31 b. All blades have a fastening hole FH at their rear ends, through which mounting screws 39 a and 39 b fasten them to blade supports 22 a and 22 b (as shown on FIG. 7).

List of exchangeable blades may also include concentric perforating blades (for making O-ring gaskets and washers), grommeting blades, flaring blades (neither shown) etc. There is no need to disassemble anything for changing one set of blades to another. Mounting screws 39 a and 39 b are easily accessible while Two-stage attachment is in “open” position.

The preferred embodiment of Two-stage attachment of the present invention further comprises two cheeks, side plates, or fulcrum plates 40R and 40L, each featuring two master pivot holes 41 a and 41 b (41Ra and 41Rb, 41La and 41Lb), two slave pivot wells 42 a and 42 b (42Ra and 42Rb, 42La and 42Lb) and two mounting shaft wells 43 a and 43 b (43Ra and 43Rb, 43La and 43Lb) of which centers are located in pairs with respect to a longitudinal axis of symmetry of the fulcrum plate (shown on FIG. 8).

Master pivot holes 41Ra, 41La, 41Rb and 41Lb maintain their diameter throughout an entire thickness of fulcrum plates 40R and 40L, and walls of these holes are smooth. Unlike that, slave pivot wells 42Ra, 42La, 42Rb and 42Lb and mounting shaft wells 43Ra, 43La, 43Ra and 43Rb have uniformly different diameters and threads, as it is explained below in detail. Mounting shafts 44 a and 44 b are dimensionally and physically identical to slave pivots 24 a and 24 b and interchangeable with them.

Fulcrum plates are positioned parallel and next to each other as if they were one another's plane mirror reflection, barring that each threaded well is opposed by it's corresponding smooth-walled well. The parts heretofore are assembled demountably into a sandwich-like structure, in such order that master pivot holes 41Ra and 41La are accommodating master pivot 17 a (41Ra-17Ra, 41La-17La) of cam lever 21 a, master pivot holes 41Rb and 41Lb-master pivot 17 b (41Rb-17Rb, 41Lb-17Lb) of cam lever 21 b, slave pivot wells 42Ra and 42La-slave pivot 24 a of blade support 22 a, slave pivot wells 42Rb and 42Lb-slave pivot 24 b of blade support 22 b, mounting shaft wells 43Ra and 43La-mounting shaft 44 a, and mounting shaft wells 43Rb and 43Lb are accommodating mounting shaft 44 b. Ends of positioning springs SR and SL are hooked to spring holders 16H.

Excessive lengths of slave pivots 24 a and 24 b are compensated by slave pivot wells 42Ra, 42La, 42Rb and 42Lb, of which wide portions are being accordingly deep. In exactly the same manner excessive lengths of mounting shafts 44 a and 44 b are compensated by mounting shaft wells 43Ra, 43La, 43Rb and 43Lb. Narrow portions of slave pivot wells 42Ra and 42 Lb, and, in a crosswise fashion, mounting shaft wells 43La and 43Rb are threaded, and narrow portions of pivot wells 42Rb and 42 La, and mounting shaft wells 43Ra and 43Lb are smooth so that fasteners 45 (same numeral for all four) can be inserted from outer sides of fulcrum plates 40R and 40L and tightened.

Depth of wide portions of slave pivot wells 42Ra, 42La, 42Rb and 42Lb and of mounting shaft wells 43Ra, 43La, 43Rb and 43Lb is calculated in such way that when fasteners 45 are tightened securely, a play of approximately 0.02-0.03 mm remains between inner walls of fulcrum plates 40R and 40L for cam levers 21 a and 21 b and blade supports 22 a and 22 b to allow for their friction-free movement. Additional strength is given to the assembly by retaining rings 46 (same numeral for all four).

Fully assembled preferred embodiment of Two-stage attachment of the present invention is shown on FIG. 6. It is mounted onto pad eyes of face flange FF of power mechanism (like that, but not limited to, shown on FIGS. 10A-B), a plurality of mounting and quick-connecting arrangements can be implemented, their possible designs are subject to separate patent application.

It must be emphasized here that all above described parts (except shearing blades 35 a and 35 b, perforating blades 37 a and 37 b and labeling blades 38 a and 38 b) are identical to their counterparts and therefore perfectly interchangeable, i. e., there is no difference between “upper” and “lower” or “right” and “left”. Suffixes “a”, “b”, “R” and “L” are serving merely for better orientation, except those cases that are listed above in parenthesis.

OPERATION OF THE PREFERRED EMBODIMENT

A normal, operation-ready position of the preferred embodiment of Two-stage attachment is “open” (shown on FIG. 10A). Actuating cam 47 is fully retracted and touching rollers 18 by it's very tip. Positioning springs S are under minimal tension, to suffice merely for preventing loose movements.

Cam levers 21, blade supports 22 and exchangeable blades of any of above described sets are at this point at a maximum angle with each other. Blade beds 22Y, to the contrary, are parallel mutually as well as to the theoretical longitudal axis of Two-stage attachment, as shown on FIG. 9A. The importance of this feature is explained at the end of “Operation . . . ” chapter. Yielding surfaces 22Y are kept in contact with pushing surfaces 15X by linking springs 30. Slave pivots 23 are in lower ends of apertures 24.

Utilization of Two-stage Method of present invention allows for the angle between open blades, regardless of a size of the Attachment, to range from 14 to 16 degrees (against 22 to 24 degrees of most of prior art). This is very important for elimination of uncontrollable “slipping” of a material (that one attempts to cut) further away from pivots of blades of typical prior art cutters. Such well known and rather pesky effect causes points of applied force to be moved as well, thus necessitating an unreasonably large force for making a cut plus substantially increasing structural tensions within the tool. Besides that, higher angle between open blades complicates, for instance, implementation of perforating or grommeting blades.

As linear impetus is imparted to actuating cam 47, it engages rollers 18. Cam levers 21 thus receive force that urges them to rotate around pivots 17, increasing tension of positioning springs S. A counter-directed vectors of force naturally materialize on cams 15. It happens so that centers of aforementioned imaginary concentric circumferences geometrically, and therefore physically, coincide with points from which these vectors are projected. Cams 15 push blade supports 22, the latter consequently receive movements towards “closed” position, and blades of installed configuration are cutting, squeezing or otherwise deforming the work piece.

These movements are resulting from “pushing and sliding” action occurring between pushing surfaces 15X and yielding surfaces 22X, and in addition, from slave pivots 23 doing their job of maintaining a functional attitude of blade supports by guiding their apertures 24. Blade supports 22 are thereupon not only commencing mutually approaching motion, but also being somewhat dragged, or retracted, into the Attachment. During a designing process a distance of this travel can be increased or decreased by a positioning of above described pares of imaginary concentric circumferences accordingly closer to or further from each other.

A beneficial effect of this linear movement is that, providing the thickness of a work piece (in this case, medium hard steel bolt, rod or bar intended to be cut in the crushing mode) does not exceed a recommended maximum for a given size of the Two-stage attachment, this work piece shall, upon being inserted between opened blades, touch not only blade's cutting edges but also frontal edges of fulcrum plates 40 (shown on FIG. 9A). Therefore, in the very beginning of a cut an advantage of this horizontal inward movement of blade supports 22 is taken, as blades are not just squeezing the work piece but making some sawing effort as well.

Most cutters of prior art allow for such effect to take place only when the work piece is of about twice as lesser thickness then their advertised capacity. One skilled in the art can appreciate the following fact: two-stage attachment of the present invention, designed for cutting maximum of 10 mm diameter of steel bolt and made of average quality steel, is being of the same width, lesser overall thickness and notably smaller length then store-purchased bolt cutter of advertised 10 mm maximum, yet meets the above outlined criteria.

But when Two-stage attachment is used, for instance, in it's perforating mode, too long of the inward movement of blades reduces a range of widths of a field between an edge of sheet metal and a row of holes punched in it. It is therefore advised to keep such distance at a reasonable “golden middle” of approximately ⅓ of a recommended maximum thickness of work piece, as explained.

Another important advantage of Two-stage method is a superiority of it's available lever ratio over most of prior art. Typical store-purchased bolt cutter has this ratio ranging approximately from 2.7 to 3.5 depending on size and thickness of work piece. Two-stage attachment of above mentioned 10 mm capacity cuts 10 mm bolt at lever ratio of approximately 5.2, thereby significantly reducing force needed for it's operation. This is especially important for a manually operated version of Two-stage attachment described below.

FIG. 10B reflects “closed” position of Two-stage attachment. Actuating cam 47 is fully extended, rollers 18 are at furthermost points from it's tip. Positioning springs S are under maximum tension and cam levers 21 are mutually parallel. So are blade supports 22, but not blade beds 22Y. These are at this point at their maximum angle with each other (shown on FIG. 9B). It is yet another notable advantage of Two-stage attachment that, at the very start of the movement of blade supports 22 towards each other, blade beds 22Y are “locking” blades inward. This optimizes a distribution of structural tensions while avoiding any need for strong fasteners between blade and blade support and thereby defeats exchangeable blade mounting methods of prior art. Slave pivots are here in higher ends of apertures 24.

As linear impetus to actuating cam 47 ceases to present, and it starts retracting, a reverse of the above shown process begins. Positioning springs S return cam levers 21 into “open” position, and linking springs 30 maintain yielding surfaces 22X in full contact with pushing surfaces 15X. Upon complete retraction of actuating cam 47 Two-stage attachment is again in “open” position.

ADDITIONAL EMBODIMENT—DESCRIPTION AND OPERATION

While in the preferred embodiment of Two-stage attachment an attitudes of “upper” and “lower” halves relative to each other are, at any given moment, maintained by actuating cam 47, thus allowing an advantage of employing short, independently pivoted blade supports 22 to be taken, this is not the case in manually operated version. Here, blade supports must be mutually linked since it shall otherwise result into uncontrollable play, inevitable whenever four or more pivot points are movably connected into enclosed series.

Consequently, jointly pivoted blade supports 48 a and 48 b are introduced (shown on FIG. 12) Their pivot ends are longer then those of individually pivoted blade supports 22 a and 22 b because otherwise the advantage of low angle between opened blades will be lost. Each featuring single horizontally offset pad eye 49 a and 49 b of exactly twice as lesser thickness than that of blade support. Common slave pivot 50 is of simple cylindrical shape, it's length exceeds the thickness of blade supports by approximately ½. In any other feature jointly pivoted blade supports 48 are entirely similar to blade supports 22.

Manually actuated cam levers 51 a and 51 b differ from cam levers 21 in practically the same manner as do jointly pivoted blade supports 48 from blade supports 22, barring single pad eyes 52 a and 52 b are not offset, and thickness of the latter is subject to a rather flexible determination.

Lesser fulcrum plates 53R and 53L of heart-like shape (shown on FIG. 13) are also essentially resembling fulcrum plates 40R and 40L, but instead of slave pivot wells 42 they have pivot grooves 54R and 54L. Immediately neighboring these grooves, at very tips of “heart”, are fastener holes 55R and 55L.

When manual version of Two-stage attachment is assembled, common slave pivot 50 is movably connecting offset pad eyes 49 a and 49 b together. The excessive length of common slave pivot 50 is compensated by pivot grooves 54R and 54L so that unobstructed linear movement of the former within the latter is granted.

Threaded spacer 56 is placed between fastener holes 55R and 55L, short fasteners 57 are then inserted and tightened securely, retaining rings 46 installed. Single pad eyes 52 a and 52 b are mounted onto either store-purchased or custom made handles and the tool is ready to function in the mode determined by whatever set of blades is installed. Fully assembled manually operated Two-stage attachment of the present invention is shown on FIGS. 11A-B.

There is an option of making blades as one piece with blade supports (shown on FIGS. 14G-K). Exchangeability then remains, but Two-stage attachment must be disassembled in order to replace such combined blades. Still within minutes one mode of operation can be swapped to another.

It shall be left at a discretion of each individual manufacturer to decide, depending upon his/her marketing targets and available materials and technologies, how many sizes of Two-stage attachments he/she deems expedient to make, and which of these sizes are feasible to be made with exchangeable blades versus employing blade support and blade as one piece.

It is, however, helpful to consider the following: assuming an average hardened steel alloy as being a material of choice and lever ratio of 5.1-5.2 is not to be sacrificed, the use of Two-stage method of the present invention permits one skilled in the art to design a tool capable of cutting steel bolt of over 16 mm in diameter and ready for use with handles of conventional store-purchased bolt cutter of ½ in (12.7 mm) advertised capacity while having lesser overall dimensions than the same.

Two-stage attachment made within these dimensions in power driven version can deal with bolts over 18 mm. A sole factor responsible for the difference between capacities of manual and power-driven versions is the width of mounting pad eyes of handles of store-purchased cutters. If Two-stage attachment and it's handles are made by the same manufacturer, such difference shall not exist.

Higher quality steel alloys and, especially, titanium alloys and composite materials present far more lucrative range of size/capacity ratios, putting a target of cutting 1 inch bolt or rebar with hand-held tool within a comparatively effortless reach.

MODIFICATIONS AND ALTERNATIVE EMBODIMENTS

Numerous changes and improvements can be made without a departure from scope and spirit of the present invention and it's Mechanical method. A list of these include, but not limited to, the following:

-   -   if the size of Two-stage attachment is not a priority, or high         tensile strength material is chosen, then instead of right (17R)         and left (17L) shafts each of master pivots 17 a and 17 b simply         comprises single shaft that protrudes through a hole in cam         lever 21,     -   retaining rings 46 are substituted by pivot caps screwed into         accordingly shortened master pivot shafts 17Ra to 17Lb, in order         to further reduce overall thickness of Two-stage attachment,     -   in order to add safety and enhance aesthetical appearance of         manually operated version, it is so designed that when not in         use and in “closed” position, there are no sharp fang-like         portions of blade supports 48 sticking out,     -   positioning springs S assume another shape (or are eliminated         altogether should actuating cam 47 incorporate guide rails for         rollers 18),     -   rollers 18 are sacrificed in favor of smaller sliding cams, thus         allowing to reduce width of Two-stage attachment while keeping         (and even boosting) it's capacity,     -   tail ends of fulcrum plates 40 have aligning rails to ensure         play-free movement of actuating cam 47, or such rails are         arranged on face flange FF,     -   roller-engaging edges of actuating cam 47 are convex from tip to         outer corners so that upon cam's 47 advance Two-stage attachment         is closing faster with lesser force at the start and slower with         greater force at the end, or these edges are wavy and blades         pulsate while closing,     -   cam slots 27, blade support slots 28 and linking springs 30 are         unnecessary if there are spring arrangements constantly urging         blade supports 22 (or jointly pivoted blade supports 48) into         “open” position, regardless of position of cams 15,     -   triple-layer blade supports are enclosing thinner cam levers         within two outer layers (each 1-1.5 mm thick), thus eliminating         need for slave pins 29 aa and 29 bb,     -   jointly pivoted blade supports 48 each have more than one offset         pad eye 49 so that the former are pivotably connected in         interlocking manner,     -   instead of round holes, pad eyes 49 featuring apertures of the         same kind as those of blade supports 22, while pivot grooves 54         of lesser fulcrum plates 53 are getting replaced by round wells         (like that of fulcrum plates 40),     -   there is one fulcrum plate carrying double-layer cam lever-blade         support couples on both sides of the former, and so on.

Two-stage method of the present invention can also be used to design a stationary (as opposed to hand-held) implement of a much larger size and capacity. A bench-mounted frame shall than carry out the function of fulcrum plate of Two-stage attachment and only one cam lever, blade support and blade will be sufficient. Big single handle must than be pivoted within the same frame in the way similar to common slave pivot 50-pivot grooves 54 arrangement of the manual version.

Another possible embodiment has three or more cam lever-blade support couples enclosed into torus-, or doughnut-shaped fulcrum ring. Tool like this can be used for precision crimping in various situations where stationary equipment is not an option. Torus-like fulcrum ring can just as well accommodate cam lever-blade support couples turned “inside out” as to create, instead of squeezing, an expending effort.

MECHANICAL METHOD OF TWO-STAGE ATTACHMENT

Two-stage method of the present invention is, essentially, a way of arranging more efficient utilization of common physical principal of lever. Some comparisons to above discussed prior art are necessary for better illustration.

From “open” to “closed” positions of widely used bolt cutter, it's mounting pad eyes MP (shown on FIG. 11 b) do travel certain sectorial distance determined by a radius between their centers and their pivot and, also, by their outer diameter. For the purposes of this chapter, these shall be deemed constant.

Another important radius is from a pivot center of typical blade of such cutter to a center of this blade's own mounting pad eye. The longer it is, the narrower is a sector of blade's movement and, consequently, available range of capacities versus size of the tool.

On the other hand, the aforementioned radius's being shorter results into undesirably large angle between cutting edges of opened blades and, moreover, reduction of tool's overall lever ratio. This is where the substance, novelty and primary advantage of Two-stage method can be best demonstrated to one skilled in the related art and familiar with above disclosed description.

It does, effectively, split the typical single blade into two independently pivoted members. Significantly shorter (thinner, narrower and lighter) cam levers 21 enjoy far greater sector of travel around pivots 17 then do single blades mounted to the same set of handles. The difference, if one wishes, is made at the area of contact between cams 15 and blade supports 22 where, due to the very nature of rotationally slidable joints, the ability to eliminate above sited faults of single blade (by establishing most favorable opening angles) is granted and practically no dimensional sacrifices are sustained.

As shown on FIG. 9A by dashed circumference CTA, cams 15 do not even fully occupy their own theoretical area. Depending on the material of which the tool is constructed, such area (and therefore overall width of the tool) can be lessened yet further harmlessly, i. e. to no loss of lever ratio or capacity. To the contrary, it creates additional resource of width for blades so these, being expendable anyway, can be made of cheaper material.

Dashed circumference PATA of FIG. 9B shows theoretical area of eccentrically pivoted boss of prior art of adequate lever ratio, which also commands additional area for it's enclosure (shown on FIGS. 2A-C). It is quite evident that, within hereby scrutinized dimensions, such boss barely leaves enough room for sufficiently rigid wholesome blades of FIGS. 14G-K, much less for those of FIGS. 14B-F. The illustration is summoned to demonstrate interdependent nature of seemingly separate aspects of Two-stage method.

Furthermore, two-stage method permits for cam's 15 traveling through narrower sector than that of circular boss, and for most effective positioning of this sector depending of the purposes of each particular application.

Having thus described a preferred and alternative embodiments, it should be apparent to those skilled in the art that certain advantages of the described apparatus and method have been achieved. It should also be appreciated that various modifications, adaptations, and other embodiments thereof may be made within the scope and spirit of the present invention. The invention is further defined by the following claims. 

1. A two-stage attachment comprising: one or more couples formed by a pivoted force-multiplying member of a first stage and a pivoted force-applying member of a second stage, each force-multiplying member comprising a planar sectorial cam having curved force-imparting surface on its working edge, the force-multiplying member further comprising a first stage pivot and means for receiving an input force imparting a rotation to the force-multiplying member about the first stage pivot, the force-applying member comprising curved force-receiving surface on an edge facing the force-multiplying member of the couple and corresponding to its respective curved force-imparting surface, the force-applying member further comprising a second stage pivot and a supporting surface, wherein the supporting surface is on an edge opposing the force-receiving surface and facing away from the force multiplying member of the couple, and wherein the supporting surface is adapted to retain a working member for deforming a workpiece, the two-stage attachment further comprising one or more pivot supporting members within which force-multiplying member-force-applying member couples are located, wherein, when the input force is imparted to the two-stage attachment, each force-multiplying member, while commencing partial rotation around its first stage pivot, causes its sectorial cam to push against the force-receiving surface of respective force-applying member thereby urging the force-applying member to rotate partially about its second stage pivot and to push the working member against the workpiece, and wherein structural tensions are evenly distributed throughout a material of the force-applying member.
 2. The two-stage attachment of claim 1, wherein the input force is imparted by any of a mechanical source, manual effort, and both.
 3. The two-stage attachment of claim 1, wherein the working members are demountable from their respective force-applying members, are made as one piece with their respective force-applying members, or both.
 4. The two-stage attachment of claim 1, wherein the force-imparting surface of each force-multiplying member is convex and the force-receiving surface of respective force-applying member is concave, or wherein the force-imparting surface of each force-multiplying member is concave and the force-receiving surface of respective force applying member is convex.
 5. A mechanical method of arranging energy-efficient two-stage force multiplication within limited spatial dimensions while simultaneously achieving multifunctional properties for a single tool. 